Copy the page URI to the clipboard
Casassus, Simon; Vidal, Matías; Arce-Tord, Carla; Dickinson, Clive; White, Glenn J.; Burton, Michael; Indermuehle, Balthasar and Hensley, Brandon
(2021).
DOI: https://doi.org/10.1093/mnras/staa4016
Abstract
Centimetre-wavelength radio continuum emission in excess of free–free, synchrotron, and Rayleigh–Jeans dust emission (excess microwave emission, EME), and often called ‘anomalous microwave emission’, is bright in molecular cloud regions exposed to UV radiation, i.e. in photodissociation regions (PDRs). The EME correlates with infrared (IR) dust emission on degree angular scales. Resolved observations of well-studied PDRs are needed to compare the spectral variations of the cm-continuum with tracers of physical conditions and of the dust grain population. The EME is particularly bright in the regions of the ρ Ophiuchi molecular cloud (ρ Oph) that surround the earliest type star in the complex, HD 147889, where the peak signal stems from the filament known as the ρ Oph W PDR. Here, we report on Australia Telescope Compact Array observations of ρ Oph W that resolve the width of the filament. We recover extended emission using a variant of non-parametric image synthesis performed in the sky plane. The multifrequency 17–39 GHz mosaics reveal spectral variations in the centimetre-wavelength continuum. At ∼30 arcsec resolutions, the 17–20 GHz intensities tightly follow the mid-IR, m), despite the breakdown of this correlation on larger scales. However, while the 33–39 GHz filament is parallel to Infrared Array Camera 8 μm, it is offset by 15–20 arcsec towards the UV source. Such morphological differences in frequency reflect spectral variations, which we quantify spectroscopically as a sharp and steepening high-frequency cutoff, interpreted in terms of the spinning dust emission mechanism as a minimum grain size
Å that increases deeper into the PDR.
Viewing alternatives
Download history
Metrics
Public Attention
Altmetrics from AltmetricNumber of Citations
Citations from DimensionsItem Actions
Export
About
- Item ORO ID
- 75154
- Item Type
- Journal Item
- ISSN
- 1365-2966
- Project Funding Details
-
Funded Project Name Project ID Funding Body Not Set Not Set LEVERHULME The Leverhulme Trust - Academic Unit or School
-
Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM) - Copyright Holders
- © 2021 Simon Casassus et al.
- SWORD Depositor
- Jisc Publications-Router
- Depositing User
- Jisc Publications-Router